1. Field of the Invention
This invention relates generally to a video presentation tool, and more particularly, relates to a presentation apparatus for converting a computer video signal to a video signal.
2. Description of the Prior Art
Nowadays, the computer is frequently used for processing many kinds of data, and it is also necessary to show the data on a display device having a large screen in a presentation. The data may be a picture, a photograph or a document. The configuration of the traditional converting device used with the computer and the video display device is shown in FIG. 1, in which the data of the analog display format is transmitted from the personal computer 10 to the converting device 11. Because the signal displayed by the monitor must be an analog format, the data is transformed to the analog display format by the personal computer 10. The converted data is then transmitted to the monitor 13 of the personal computer 10 by the converting device 11, and transformed into a video format signal simultaneously. The aforementioned video format signal is thus fed to the video display device 15 to illustrate the data. Because the traditional converting device using the traditional technologies can not process the data, the image shown on the display in the presentation is identical with the image on the monitor of the computer used by presenter. The traditional converting device directly shows the data, which is transmitted from the computer to the monitor supported by the presenter.
According to the traditional converting device mentioned above, the point of the presenter can not be clearly expressed in the image on the display, the viewer in the presentation can hardly catch the idea of the presenter using the traditional converting devices. In order to solve the problems mentioned above, some kinds of programs in the personal computer 10, such as Micro-soft power point, are designed and used to further process the data. Thus the presenter can use the functions such as zoom and pan or highlight a portion of data. Though the aforementioned functions can be applied when the traditional converting device is used, the compatibility between the software and the data is a problem. The format of most data is usually unacceptable for the presentation software. For example, if the data is a circuit diagram, a waveform, or a block diagram, the aforementioned functions can not be used. Moreover, the installation of the software is not convenient for the presenter. So the software designed for a presentation is not practical.
In the other type of the traditional converting devices, when the picture transferred from the data is enlarged, the picture is first divided into several portions. If the presenter wants to zoom in a portion of the picture, the presenter uses the remote controller of traditional converting device to select one portion of the picture, and the converting device enlarges the selected portion on the video display device. Because the divided portions are already determined in the converting device, the presenter can only highlight a portion of the picture according to the predetermined portions on the remote controller of the traditional converting device. In other words, the presenter must search for a while when he wants to show a portion of the picture, so the presentation is interrupted for a while. If the selected area that is to be zoomed can be highlighted first, it is easy for the presenter and the viewer to search for the selected area.
In addition, though the pointer can be used in a presentation to point out a position on the picture of the video display device, the presenter still has to purchase and bring the pointer. Furthermore, although the functions such as zoom and pan or other functions can be used in the prior art, however, the presenter can only select a portion of the picture according to the predetermined portions. In the traditional converting device, the picture converted from the data is divided into 9 portions, and the presenter can only select one of them to implement the functions such as zoom, pan or other functions.
In some applications, it is necessary to show different portions of a picture converted from the data, yet the presenter using traditional converting device can not illustrate an optional portion or more portions of the picture on the video display device. Thus the presenter is forced to change from a portion to the other portion of the picture, and the viewer may be confused. Furthermore, some presenter used to utilize projector can not accustomed to handle the personal computer and the converting device, because the presenter used to apply an opaque material to cover a partition of a slide to show the other partition of the image on the display. When the presenter wants to show more parts of the covered partition of the slide, the presenter can slowly pull down the opaque material to show more parts of the covered partition of the slide. The aforementioned functions can not be implemented in the traditional converting device, so it is inconvenient for the presenter that used to utilize the projector. In addition, the traditional converting device can not generate a light spot on the picture, so the presenter can not highlight an optional position on the display without a pointer.
For the mentioned above, there are some elementary disadvantages in the traditional converting device. At first, the traditional converting device can not show the edge of the selected area, no matter how many selected area are shown on the video display device. So the presenter can not highlight a selected area among a plurality of selected areas of a picture. Thus the presenter can not separately show the data in the different selected areas that is proceeded with different image process, such as inverting tone of color of pixel or brightness of pixel. So the viewer can not compare the image in the different selected area. In addition, the function of a pointer can not be installed in a traditional converting device. And the traditional converting device can not be used to imitate the action of a traditional projector.